In others words, we're extraordinarily lucky that this particular ultra-wealthy person has decided to do good things with (some) of their money. But grounding moral and humanitarian progress on a steady stream of luck seems shortsighted.

It's most certainly not a fluke that the mega rich are solving problem governments can't or won't.

There is no "can't or won't" on a global scale: some countries have, others haven't as a function of their means. The fact that ultra wealthy individuals have better means than entire countries is an indictment of the state of affairs, not praise.

Edit: To elaborate on the above: eradicating polio isn't something that democratic, liberal countries are uniquely good at. Autocratic and despotic governments have also historically been good at it and have aggressively pursued it, because paralyzed citizens just aren't very useful. Countries that don't pursue eradication are historically ones that just lack the means (whether that's money, or infrastructure, or whatever), not ones with specific political structures.

That is exactly "can't or won't". The USA or China certainly "can" fix these issues in Africa if they want to but they "won't". But the African countries themselves obviously don't have this capability thus they "can't" fix it.

> The fact that ultra wealthy individuals have better means than entire countries is an indictment of the state of affairs, not praise.

Why is this an indictment. This is not self evident at all to me. The opposite is true from my perspective. This story and initiatives like the giving pledge very clearly show me that that the mega rich are doing things no country is doing. And thus these problem would remain unsolved if they would not be here.